Gas caps are mechanically coupled to the upper, open end of a fuel tank filling neck or tube to seal off the tank interior yet provide access for filling at the service station. Access to the filling neck is external of the automobile through a pivotable flap or door within the vehicle body. Such flaps or doors may carry a lockable lock for preventing access to the cap. Additionally, the integrity of the fuel system is maintained by key lockable gas caps.
Over the years, gas caps which include a combination lock have been devised for closing off the open end of the fuel tank filling neck. The following patents are exemplary of known combination type gas caps:
U.S. Pat. Nos. 965,590 Lokody, 1,403,328 Keplinger, 1,898,373 Jay, 2,229,366, Brannon et al, 2,437,674 Armbruster, 2,588,605 Armbruster, 3,802,231 Pig, and 3,985,007 Gerdes.
Certain of these patents are exemplary of the development of the art. In U.S. Pat. No. 3,802,231, a series of manually rotatable coaxial actuating rings each carrying a series of external reference marks are placed about a member including a non-manually rotatable external surface carrying at least one reference mark. Unscrewing of the cap and thus unlocking is effected upon proper angular placement of the rings relative to each other and the balance of the locking cap structure.
U.S. Pat. No. 2,229,366 is directed to an inverted U-shaped metal cap fittable about the open end of the fuel tank filler neck, which neck includes a radially inwardly directed rim. The cap mounts internally a radially projecting projectable bolt and carries a rotary dial on the exterior of the cap and at the center thereof. The dial is rotated to dial in a combination for positioning of multiple disks which, in turn, permit or prevent radial shifting of the bolt via an external slide fixed to the bolt to project or retract the end of the bolt from a position beneath the radially inwardly directed rim and thus to free the cap or to retain it on the neck.
While such combination locks are capable of effectively locking and unlocking the cap to the filler neck, the requirements to rotate the dial in multiple directions and to given degrees in sequence requires time.
Additionally, combination locks have been developed using multiple depressible push buttons which may be required to be selectively and/or sequentially depressed. The number of push buttons and given sequence may vary depending upon the combination employed.
It is therefore a primary object of this invention to provide a combination lock type gas cap and actuator therefor employing a plurality of depressible push buttons, in which the combination is set at the factory and the consumer cannot change the combination without breaking open the lock, the gas cap is robust and wherein, the combination lock type gas cap includes a locking mechanism which effectively couples and uncouples an externally accessible upper cap member to an externally threaded sleeve coaxially with the cap member, and rotatable on a cylindrical casing which projects from the cap member and which rotatably supports the sleeve, and wherein, the sleeve in turn is threaded into the open end of a fuel tank filling neck.